The present invention relates generally to read and write transducers, and more particularly to an improved transducer head support structure for use in helical tape recorders.
In many data and video tape recorders some automatic tracking mechanism is often used to maintain the position of the transducer head on a predetermined linear or curvilinear magnetic track. Tracking is a particularly acute problem in helical tape recorders when the recorded tracks on the tape have been distorted, as by temperature or humidity-induced dimensional changes in the tape, or by faulty tensioning mechanisms in the tape transport. In addition, specialized features of a tape recorder, such as slow-motion record and playback or stop motion playback, dictate that the head or heads jump or skip tracks in a predetermined pattern. As the head reads from successive tracks it is critically important that the head retain its alignment with the respective track to insure an optimum output of the information carried by the tape. Also operating against the accuracy of such alignment are external factors such as tape tension, tape speed, humidity, etc.
Accordingly, it is desirable to simplify the structure associated with supporting the head for tracking the individual tracks disposed on the tape, to enable the head to accurately maintain alignment with the paths of individual tracks so as to correctly read the data carried on the magnetic recording media. One well-known form of head support structure is a single cantilevered arm having one or more magnetic heads mounted at the outer end thereof. The cantilevered arm comprises a flexure member connected to a rigid member. The deflection of the cantilevered arm is caused by a linear motor disposed adjacent to the head. When the magnet associated with the linear motor is proximate to the head, the resulting magnetic interference can adversely affect the output of the head.
Furthermore, the disposition of the magnet adjacent to the head at the outer end of the head support member places a relatively large mass near the outer periphery of the scanner drum and subjects the support member to centrifugal forces associated with the rotary movement of the scanner drum. Such forces are significant for a drum rotating as high as 6000 rpm, which necessitates a bulkier structural design than otherwise would be needed.
Additionally, in a vibrational environment, the motion component parallel to the rotational axis of the scanner has a tendency to displace the head from its normal operative position. In a cantilevered structure, active servo circuits associated with head position must compensate for this motion.